<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>let</title>
	</head>
	<body>
		<script>
			//声明变量
			let a;
			let b, c, d;
			let e = 100;
			let f = 521,
				g = "iloveyou",
				h = [];

			//1. 变量不能重复声明
			// let star = '罗志祥';
			// let star = '小猪';

			//2. 块儿级作用域  全局, 函数, eval
			// if else while for
			// {
			//     let girl = '周扬青';
			// }
			// console.log(girl);

			//3. 不存在变量提升  var存在变量提升
			// console.log(song);
			// let song = '恋爱达人';

			//4. 不影响作用域链
			{
				let school = "尚硅谷";
				function fn() {
					console.log(school);
				}
				fn();
			}
		</script>
	</body>
</html>
